Spot iron ore prices rose to above $81 a tonne as Chinese steel producers restocked, although the supply of available cargoes remained high and kept a lid on gains.

Mills in China's Tangshan area in the northern Hebei province were buying more iron ore ahead of planned shutdowns at the start of November, said a trader in Shanghai.

Some steel mills in Hebei - China's top steel producing province - have been asked to reduce or suspend production during the APEC meeting in China next month to help improve the air quality in the capital Beijing, according to local media reports.

"The shutdowns may take almost two weeks and some of th mills are trying to increase production ahead of that," the trader said.

Iron ore for immediate delivery to China .IO62-CNI=SI rose 0.7 percent to $81.20 a tonne on Monday, according to data compiled by The Steel Index.

Iron ore, China's biggest import commodity by volume, has regained some ground since falling to a five-year low of $77.50 at the end of September, hit hard by abundant supply as low-cost top miners such as Rio Tinto and BHP Billiton expanded output in the face of weak demand.

The most-traded iron ore contract for delivery in January on the Dalian Commodity Exchange climbed 1.2 percent to583 yuan ($95) a tonne. Iron ore futures in Singapore also edged higher.

China's daily crude steel output reached 2.25 million tonnes in September, up 1 percent from August and the highest since the record 2.31 million tonnes in June, suggesting mills were still at close to full capacity despite a long price slump.

The most-active rebar for May delivery on the Shanghai Futures Exchange gained half a percent to 2,620 yuan a tonne.

Rebar, used in construction, hit a record low of 2,507 yuan earlier this month. The futures price remains at a steep discount to spot rebar prices, which were quoted at around 3,000 yuan a tonne on Tuesday, according to data compiler SteelHome.

"This points to rebar futures being oversold and should provide some support to rebar futures prices near term," ANZ Bank analysts said in a note.

China produced 67.54 million tonnes of crude steel in September, down 2 percent from the previous month and flat compared to the corresponding month of 2013, data from the National Bureau of Statistics showed.

Data on Tuesday also showed China's economy grew 7.3 percent in the third quarter, its slowest pace since the 2008/09 global financial crisis, as a slumping property market hit manufacturing and investment.

The slowdown reinforced expectations that Beijing will need to unveil more stimulus measures to avert a sharper slowdown.